USB-C Introduction: Charging, Display, Thunderbolt and Everything You Need to Know

What is USB-C?

The Common Interface of Consumer Electronics

USB Type-C is a new generation of USB connectors introduced in 2014 as the successor to the Type-A and Type-B that we are familiar with. The USB-C connector is smaller than its predecessors and features a symmetrical design, making it easier to plug in. Additionally, it has a high data transfer rate, which is ideal for rapidly transferring large files.

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Standard Charging Port Regulated by EU

On 5 October 2022, the European Union Parliament officially passed a law stating that consumer electronic products must have a USB-C charging port by the fall of 2024. This aims to comply with the regulation that promotes interchangeability and the same charging power design of consumer electronics products. In the fall of 2024, portable electronic devices (such as smartphones) in the European region will only be sold with Type-C interfaces, and by the end of 2025, laptops will also be regulated by the law. This will impact the consumer electronics market as the USB-C interface becomes the standard for consumer electronics.

So, let's learn more about the features and importance of the USB-C interface.

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Advantages of USB-C

Compared to traditional USB connectors, USB-C has several advantages.

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Compatibility

The biggest advantage of USB-C is that more and more devices adopt this interface, allowing users to charge their devices and transfer data across smartphones, tablets, and laptops with a single USB cable.

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USB Power Delivery 3.0

USB-C interface supports power delivery, which can be used to charge devices. The latest USB PD 3.0 version can provide up to 100W of power, sufficient for charging laptops and other high-power devices.

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High Data Transfer Rate

USB-C supports USB versions with a high data transfer rate and is suitable for rapidly transferring large files. The latest USB 3.2 version can achieve a data transfer rate of up to 20Gbps, twice as fast as the previous version.

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Reversible Connector

Another feature of USB-C is its reversible connector. Unlike earlier USB standards, the USB-C connector can be inserted either way, making it more user-friendly.

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What Is USB-C Used For?

Can USB-C Be Used for Display?

If both your USB-C device and the monitor support DP Alt Mode, USB-C to DisplayPort will not require an adapter. You can share video from your computer or smartphone to the monitor with a USB cable. An adapter will be required for USB-C to HDMI or USB-C to VGA.

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Learn more about DisplayPort and DP Alt Mode: Single Cable for USB and A/V Transmission - DP Alt Mode

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USB-C to 3.5mm Audio

USB-C interface can also be used to transmit audio. You can use a Type-C to 3.5mm cable to connect to speakers, audio devices, etc.

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Internet Connection

USB-C can also be used to share the internet. For example, a USB-C cable can be used to share the internet connection from a smartphone with a computer that doesn't have Wi-Fi capabilities.

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High-Speed Charging

USB-C can be used directly to charge mobile devices. Corresponding to USB PD technology is QC (Quick Charge) technology. Currently, the charging specifications of USB PD 3.0 technology are higher than those of QC 4+. QC charging technology is most commonly used in Android smartphones.

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File Transfer

You can transmit files from devices such as portable hard drives using USB-C without converting USB-C to USB-A to transfer data. Also, files can be transferred between a computer and a smartphone.

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Challenges Faced by USB-C

Larger Size

Although the USB Type-C interface is smaller than the Type-A, some devices still use the micro-USB due to its smaller size.

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Overheating

While the charging power of USB-C can reach 100W, it may also encounter overheating issues, requiring PTC thermistors to protect the circuit.

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Complex Specifications in the Transition Period

The USB-C interface supports multiple functions and protocols, such as USB 3.2, Thunderbolt 3, and DisplayPort. However, this complexity can lead to confusion and compatibility issues as different USB-C devices and cables may not support the same functions or protocols. During the transition period, many laptops with USB-C ports still do not support PD charging or audio/video transmission but data transfer via USB-C, despite that USB-C devices with all these capabilities will become prevalent in the future.

We will introduce the different specifications later.

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USB-C Max Length

The max length of USB-C cables depends on the standard and the required bandwidth.

• Thunderbolt 3
  A passive Thunderbolt 3 cable typically achieves a bandwidth of 40Gbps for 0.8 meters or 20Gbps for 2 meters.

• USB 3.1
  USB 3.1 Gen1 has a bandwidth of 5Gbps and Gen2, 10Gbps, allowing for transmission over 2 to 3 meters.

Generally, a higher bandwidth allows for shorter transmission distances under the same conditions.

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Common USB Symbols

Have you ever noticed the little icons marked beside the USB port? Give them more attention now that they specify the USB specifications. If the specifications of the USB ports at both ends do not match, the device may be unable to use. For example, using a Thunderbolt connector with a cable that doesn't support it may limit or disable the transmission.

Pay attention to the markings on your Type C devices, Type C charging cables/transmission cables, and Type C accessories, or check the relevant specifications to ensure smooth transmission. Different specifications of devices, charging cables, and accessories may cause transmission discrepancies.

In summary:

• The Thunderbolt 3 logo indicates that it supports DP (DisplayPort) and USB PD (Power Delivery).
• The support for DP Alt Mode determines whether video and audio transmission is possible.
• A device labeled with Thunderbolt 3 or USB 4 should support audio/video transmission, data transfer, and power delivery.

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What happens if I connect USB-C to Thunderbolt 3?

USB-C is backward compatible, meaning that devices can communicate even if the specifications at both ends differ, with the lowest standard adopted. For example, when using a smartphone labeled with USB-C SS (Super-Speed USB Type-C, supporting USB 3.0/3.1) to connect to a computer labeled with USB-C lightning symbol (supporting Thunderbolt 3), the transmission will have the following limitation:

Reduced Transmission Speed

Although Thunderbolt 3 provides high-speed transmission at 40Gb/s, the transmission rate will be limited to 5Gb/s or 10Gb/s since the smartphone only supports USB 3.0/3.1.

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Limited Functions: Inability to Transmit Video

Since the smartphone only supports USB 3.0/3.1, it can't integrate different video outputs like DisplayPort and HDMI as Thunderbolt 3 can.

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Reduced Charging Speed

The smartphone supporting USB 3.0/3.1 allows a maximum charging power of only 15 watts. In contrast, smartphones supporting Thunderbolt 3 allow a maximum charging power of 100 watts. Therefore, Thunderbolt 3 charging will be faster than USB-C charging.

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Different USB Connector Types

Apart from the latest Type-C, there are other USB connectors that we are familiar with:

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USB-A

USB Type-A is the oldest and most common USB connector. Type-A connectors are rectangular and can only be inserted in one way.

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USB-B

USB Type-B connectors are less common than Type-A connectors. They are typically used for printers and other peripherals. Type-B connectors are square-shaped with two slightly slanted corners, which are easy to identify.

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Mini-USB and Micro-USB

Mini-USB and micro-USB are smaller versions of Type-B. Generally, they are used to charge smartphones and small electronic devices.

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Learn more about: USB-A vs. USB-B vs. USB-C: What's the Difference?

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Conclusion

As the latest and most versatile USB standard, USB-C offers many advantages over older USB standards, including high-speed data transfer rates, reversible connectors, and power delivery capabilities. While it is just one of the interfaces, there are various transmission specifications that can be combined. It's similar to network cables, which have the same RJ45 connector but transmit different signals, including network, power, or audio/video.

Currently, we are in the transition period when the USB-C interface is still integrating different standards and technologies. Therefore, when using USB interfaces, it is critical to recognize their specifications to avoid limited transmission caused by the discrepancy. It is believed that the USB-C specification will become more consistent and common to use.

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USB-C FAQs

Can I use USB-C to charge my laptop?

If your laptop is labeled with Thunderbolt or PD, you can use USB-C to charge it. If not, please check the specifications of your laptop to see if it mentions USB-C PD or Thunderbolt functionality. Please remember that even if you have a laptop that supports USB-C charging, you need to choose the correct cable that supports PD or Thunderbolt functionality in order to charge successfully.

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What is USB 4?

USB 4 is the latest version of the USB standard. It uses the USB-C connector and supports high data transfer rates, DisplayPort, and power delivery. USB 4 is backward compatible with older USB standards. Overall, USB 4 becomes more similar to Thunderbolt.

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What's the difference between Thunderbolt 3 and USB-C?

Thunderbolt 3 is a different interface developed by Intel. It uses the same connector as USB Type-C but provides higher data transfer rates and advanced features.

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What's the difference between USB 3.1 and USB-C?

USB Type-C is a connector, while USB 3.1 is a standard that specifies data transfer rates of up to 10Gbps. USB Type-C can support USB 3.1, but not necessary.

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What's the difference between Thunderbolt 4 and USB 4?

Thunderbolt 4 is compatible with USB 4, but Thunderbolt 4 has higher performance requirements. USB 4 has the advantage of low or no licensing fees, while Thunderbolt 4 requires payment to Intel; products using Thunderbolt 4 may have a higher price.

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